The field of the disclosure relates generally to gas turbine engines and, more particularly, to a method and system for cooling oil in a gas turbine engine and maintaining a separation of a flammable coolant and an oxidizing coolant.
At least some known gas turbine engines include one or more oil cooling systems that are configured to cool and lubricate components of gas turbine engines. Some gas turbine engines include an air-oil surface cooler and/or a fuel-oil heat exchanger. Air-oil heat exchangers attached to the inner radial surface of the nacelle, and use fan air to cool the oil flowing through the air-oil heat exchanger. Air-oil surface coolers include fins protruding into the bypass airflow passageway that exchange heat with the relatively cold fan air.
Fuel in aircraft engines is often heated to prevent water in the fuel from freezing and to improve combustion of the fuel. In some gas turbine engines relatively hot oil is used to heat the fuel. Air has typically not been used to heat the fuel. A leak in the fuel-oil heat exchanger could put fuel and oxygen in contact with each other inside the engine. Having separate air-oil and fuel-oil heat exchangers takes up valuable space in the engine and adds weight to the engine.